I'll deal with that (usually unpleasant) situation only when I can't avoid it any longer; sometimes mangled ironically as "I'll burn that bridge when I get to it", in allusion to "burning one's bridges".

To die, or to die a loyal death (suicide) and not necessarily from a train. Sometimes taken literally, as people have died from being in front of trains. Also means to take a huge risk. Another variant is "to crawl in front of/under a moving train" which means to engage in extremely risky behavior since trains have little crawlspace underneath.

A phrase illustrating that 'good' or 'bad' is often a matter of perspective. From the belief that someone who refers to a glass as "half full" has an optimistic outlook on life, and someone who refers to the same glass as half empty has a pessimistic one

A phrase used to answer in the affirmative, implying that the questioner is silly to ask the question, as the answer is obvious. Used in many variations ("Is/Does the ___ ___?") of equally obvious nature, e.g., "Is the sky blue?"

Beyond comprehension, unintelligible. This expression was coined by William Shakespeare, who used it literally in Julius Caesar (1:2), where Casca says of a speech by Seneca, deliberately given in Greek so that some would not understand it, "For mine own part, it was Greek to me."